†Empa, Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland.
‡Department of Chemistry, University of Zurich, 8057 Zürich, Switzerland.
J Am Chem Soc. 2015 Jul 1;137(25):7970-3. doi: 10.1021/jacs.5b02262. Epub 2015 Jun 16.
The quest for enantiopure compounds raises the question of which factors favor conglomerate crystallization over racemate crystallization. Studying nucleation and crystal growth at surfaces with submolecular-resolution scanning tunneling microscopy is a suitable approach to better understand intermolecular chiral recognition. Racemic heptahelicene on the Ag(100) surface shows a transition from homochiral nuclei to larger racemic motifs, although the extended homochiral phase exhibits higher density. The homochiral-heterochiral transition is explained by the higher stability of growing nuclei due to a better match of the molecular lattice to the substrate surface. Our observations are direct visual proof of viable nuclei.
对手性纯化合物的探索提出了这样一个问题，即哪些因素有利于齐聚物结晶而不是外消旋体结晶。用亚分子分辨率扫描隧道显微镜研究表面的成核和晶体生长是一种更好地理解分子间手性识别的合适方法。在 Ag(100)表面上的外消旋七螺旋烯显示出从同手性核到更大的外消旋图案的转变，尽管扩展的同手性相表现出更高的密度。同手性-异手性转变是由于生长核的稳定性更高，因为分子晶格与基底表面的匹配更好，从而解释了这一转变。我们的观察结果是可行核的直接视觉证据。
